1. Field of the Invention
This invention relates to calcium aluminosilicate glasses which, in finely divided form, react with aqueous polycarboxylic acids and set to form a solid mass. Cements formed from glasses of the invention and polycarboxylic acids are particularly suitable for use in splinting agents.
2. Description of the Prior Art
It is now well established that splinting bandages can be prepared from water hardenable cement compositions in which the reactive components are a glass and a polycarboxylic acid. The most successful version of this form of bandage is described in British Pat. No. 1,554,554 and the glasses used in the cements are described in British Pat. No. 1,554,555. One example of such a bandage using such a glass is available as "CRYSTONA" from T. J. Smith & Nephew of Welwyn Garden City and Hull, U.K. This existing product has many excellent properties resulting from the use of a calcium fluoroaluminosilicate glass, as described in British Pat. Nos. 1,554,554/5, to provide a composition which remains workable for a period (the gel time) sufficient to enable the bandage to be placed in position, but then sets quite rapidly. Unfortunately the need to incorporate quantities of fluorine in the glass to achieve an acceptable gel time and set time adds substantially to the cost of the production process. This is because fluorine is regarded as an atmospheric pollutant and glasses containing significant quantities of fluorine need to be made under strictly controlled and hence expensive operating conditions in order to protect the environment.